The answer you are looking for is under option A
The statement that is not true is: A healthy ecosystem can support an unlimited number of life forms.
Any ecosystem has its limits. No matter is a healthy, in perfect shape, and very large ecosystem, there's always a limit as to how much life forms can the ecosystem support. If the number of life forms surpasses the ability of the ecosystem to support them, than the ecosystem will crash, be destroyed, and experience a lot of changes, with the death of lot of life forms involved in the process as well.
There isn't such thing as an ecosystem that has the ability to support an infinite number of life forms, there's only ecosystems that are able to support limited number of life forms.
Answer:
The Sahel is the ecoclimatic and biogeographic zone of transition in Africa between the Sahara to the north and the Sudanian Savanna to the south. Having a semi-arid climate, it stretches across the south-central latitudes of Northern Africa between the Atlantic Ocean and the Red Sea. Wikipedia
Area: 1.179 million mi²
The Sahel has a tropical, hot steppe climate (Köppen climate classification BSh). The climate is typically hot, sunny, dry and somewhat windy all year long. The Sahel's climate is similar to, but less extreme than, the climate of the Sahara desert located just to the north.
Explanation:
